Semisynthetic derivatives of massarilactone D with cytotoxic and nematicidal activities

• Rémy B. Teponno,
• Sara R. Noumeur and
• Marc Stadler

Beilstein J. Org. Chem. 2025, 21, 607–615, doi:10.3762/bjoc.21.48

• derivatives 2–8. Reagents and reactions conditions: a) (CH3CH2)3N/DMAP and methacryloyl chloride in CH2Cl2; b) (CH3CH2)3N/DMAP and cinnamoyl chloride in CH2Cl2; c) (CH3CH2)3N/DMAP and 4-bromobenzoyl chloride in CH2Cl2; d) (CH3CH2)3N/DMAP and trans-2-methyl-2-butenoyl chloride in CH2Cl2; e) (CH3CH2)3N/DMAP and

Sequential two-step, one-pot microwave-assisted Urech synthesis of 5-monosubstituted hydantoins from L-amino acids in water

• Wei-Jin Chang,
• Sook Yee Liew,
• Thomas Kurz and
• Siow-Ping Tan

Beilstein J. Org. Chem. 2025, 21, 596–600, doi:10.3762/bjoc.21.46

• methylated amino acids and carbamates (65–75%) [9] or cyanobenziodoxolone (CBX) (54–88%) [10]. Reactions using 1,2-diaza-1,3-dienes, amines, and isocyanates (47–76%) [11], as well as α-amino amides with triphosgene or carbonyldiimidazole (CDI) (41–80%) [12], have also been explored. Other strategies include

• copper(I)-catalyzed reactions (48–71%) [13] and the four-component Ugi reaction [14] yields 48–71% and 27–67%, respectively. In addition, pyroglutamates with isocyanates, which provide exceptionally high yields (97–99%) [15], and dipeptides have been utilized in triflate-activated Mumm’s rearrangement

• substrate reactivity, minor side reactions, or minor losses during microwave irradiation. The remaining part may be caused by factors such as slight volatilization or incomplete conversion under specific use conditions. We found the synthetic procedure facile as the less polar hydantoin products (H2a–c, H2e

Formaldehyde surrogates in multicomponent reactions

• Cecilia I. Attorresi,
• Javier A. Ramírez and
• Bernhard Westermann

Beilstein J. Org. Chem. 2025, 21, 564–595, doi:10.3762/bjoc.21.45

• /bjoc.21.45 Abstract Formaldehyde emerges as a cornerstone in multicomponent reactions, mainly prized for its robust reactivity. Yet, alongside these beneficial traits, this highly reactive C1-building block raises concerns, primarily regarding its toxicity. One notable issue is the challenge of

• controlling the formation of undesired byproducts during its reactions. This review explores alternative C1-building blocks that serve as surrogates for formaldehyde, aiming to mitigate some of the challenges associated with its use in multicomponent reactions. By identifying these alternatives, toxicity

• concerns and improved reaction control can be addressed, paving the way for more efficient and sustainable synthetic methodologies. Keywords: cascade reactions; formaldehyde surrogates; green chemistry; heterocycles; multicomponent reactions; Introduction Organic chemistry is a mature discipline that has

Study of the interaction of 2H-furo[3,2-b]pyran-2-ones with nitrogen-containing nucleophiles

• Constantine V. Milyutin,
• Andrey N. Komogortsev and
• Boris V. Lichitsky

Beilstein J. Org. Chem. 2025, 21, 556–563, doi:10.3762/bjoc.21.44

• structure of used N-nucleophile various types of a heterocyclic system can be obtained. A large number of examples of reactions with substituted amines have been reported in the literature. Generally, this process includes opening of the furanone ring followed by cyclization to the pyrrolone moiety [6][7][8

• pyrrolones such interaction can lead to pyridazinone systems [10][11]. Despite on the plenty of reactions with nitrogen-containing nucleophiles there is only one example of recyclization using furanone with a carbonyl group at position 3 (Scheme 1a, previous work) [6]. However, no work on this type of

Asymmetric synthesis of β-amino cyanoesters with contiguous tetrasubstituted carbon centers by halogen-bonding catalysis with chiral halonium salt

• Yasushi Yoshida,
• Maho Aono,
• Takashi Mino and
• Masami Sakamoto

Beilstein J. Org. Chem. 2025, 21, 547–555, doi:10.3762/bjoc.21.43

• of its unique interaction in organic synthesis. Chiral halonium salts have been found to have strong halogen-bonding-donor abilities and work as powerful asymmetric catalysts. Recently, we have developed binaphthyl-based chiral halonium salts and applied them in several enantioselective reactions

• developed chiral halonium salts and applied them to asymmetric reactions such as vinylogous Mannich reactions of cyanomethylcoumarins 6 with isatin-derived ketimines 7 [33][35] and 1,2-addition reaction of thiols to ketimine [34], which formed the corresponding products 8 in high yields with high to

• tetrasubstituted carbon stereogenic centers [42][43][44][45][46]. In 2011, Shibasaki, Matsunaga and co-workers reported strontium or magnesium-catalyzed stereodivergent asymmetric Mannich reactions of an α-isothiocyanato ester with ketimines, which provided the products in excellent yields and

Vinylogous functionalization of 4-alkylidene-5-aminopyrazoles with methyl trifluoropyruvates

• Judit Hostalet-Romero,
• Laura Carceller-Ferrer,
• Gonzalo Blay,
• Amparo Sanz-Marco,
• José R. Pedro and
• Carlos Vila

Beilstein J. Org. Chem. 2025, 21, 533–540, doi:10.3762/bjoc.21.41

• properties along a C=C double bond [1]. This effect has been established to be very advantageous to expand the range of reactions of different functional groups that can be coupled efficiently through a conjugated π-system. In this context, the addition reaction of vinylogous nucleophiles to carbonyl

• compounds is a significant and important reaction for the selective synthesis of homoallylic alcohols in an efficient and sustainable way [2][3]. As carbonyl compounds, alkyl trifluoropyruvates [4][5] are an interesting class of compounds that have been used in addition reactions of different nucleophiles

• diastereoselectivity at 50 °C (Table 1, entry 16). Finally, the addition of molecular sieves was evaluated (Table 1, entries 17 and 18) affording in both cases lower yields for the reaction product. We also attempted asymmetric reactions using chiral organocatalysts to achieve an enantioselective outcome; however, we

Deep-blue emitting 9,10-bis(perfluorobenzyl)anthracene

• Long K. San,
• Sebastian Balser,
• Brian J. Reeves,
• Tyler T. Clikeman,
• Yu-Sheng Chen,
• Steven H. Strauss and
• Olga V. Boltalina

Beilstein J. Org. Chem. 2025, 21, 515–525, doi:10.3762/bjoc.21.39

• -step reactions with anthraquinone starting materials [24], or by Ullman coupling reactions of acene bromides with perfluoroalkyl iodides [25]. Notably, direct UV photoinduced reactions between anthracene and perfluoroalkyl iodides in the presence of a reducing agent, Na2S2O3, yielded perfluoroalkylated

• dimeric molecules, instead of expected 9,10-(perfluoroalkyl)2ANTH [26]. To the best of our knowledge, perfluorobenzylation of anthracene has not been reported prior to this study. The only PAH perfluorobenzylations were reported by our group: with CORA using gas-phase solvent-free reactions in sealed

• ampules and with PERY using solution-phase reactions at elevated temperatures in the presence of Cu metal or another reducing agent [22]. In this study we first explored the approaches from our previous work: a high-temperature gas-phase reaction between ANTH and BnFI [18][19], and a solution-phase

Unprecedented visible light-initiated topochemical [2 + 2] cycloaddition in a functionalized bimane dye

• Metodej Dvoracek,
• Brendan Twamley,
• Mathias O. Senge and
• Mikhail A. Filatov

Beilstein J. Org. Chem. 2025, 21, 500–509, doi:10.3762/bjoc.21.37

• promising strategy for synthesizing substituted cyclobutanes without the need for ultraviolet irradiation. Keywords: bimane; [2 + 2] cycloaddition; fluorescence; topochemical polymerization; X-ray crystallography; Introduction Topochemical polymerizations refer to polymerization reactions occurring in the

• solid state, which are highly dependent on molecular packing. The concept of topochemical reactions was first introduced by Kohlschütter in 1919 [1], and topochemical polymerizations were systematically studied by Schmidt and co-workers in the 1960s and 1970s [2][3][4]. Schmidt's pioneering work

• primarily focused on [2 + 2] photocycloaddition in the solid state, making it one of the earliest known examples of topochemical polymerization and a valuable method for synthesizing substituted cyclobutanes [5]. These solid-state reactions are highly influenced by the arrangement of monomers within the

Synthesis of N-acetyl diazocine derivatives via cross-coupling reaction

• Thomas Brandt,
• Pascal Lentes,
• Jeremy Rudtke,
• Michael Hösgen,
• Christian Näther and
• Rainer Herges

Beilstein J. Org. Chem. 2025, 21, 490–499, doi:10.3762/bjoc.21.36

• switching efficiency in aqueous solutions. In order to investigate the chemistry of this promising photoswitch and to unlock further applications, we now investigate strategies for the synthesis of derivatives, which are based on cross-coupling reactions. Fourteen vinyl-, aryl-, cyano-, and amino

• -substituted diazocines were prepared via Stille, Suzuki, and Buchwald–Hartwig reactions. X-ray structures are presented for derivatives 1, 2 and 7. Keywords: cross-coupling; diazocine; N-acetyl diazocine; photoisomerization; photoswitch; thermal relaxation; Introduction Diazocines are frequently used

• biochemical reactions usually take place in aqueous environments [13]. The substitution of one CH2 group in the CH2CH2 bridge by N–C(=O)–CH3 leads to an intrinsic water solubility of the N-acetyl diazocine 1 (Figure 1) [3]. Furthermore the photoconversion of 1 shows no significant drop in pure water in

Organocatalytic kinetic resolution of 1,5-dicarbonyl compounds through a retro-Michael reaction

• James Guevara-Pulido,
• Fernando González-Pérez,
• José M. Andrés and
• Rafael Pedrosa

Beilstein J. Org. Chem. 2025, 21, 473–482, doi:10.3762/bjoc.21.34

• the literature, we found that 1,5-diketones and 1,5-ketoaldehydes have been utilized in retro-Michael reactions catalyzed by NaOH or KOH at extremely high reaction temperatures [26]. Some examples are also described under milder conditions, where the starting compounds are obtained with good chemical

• yields [27]. These reactions have been utilized in the enantioselective synthesis of aryl sulfoxides through the arylation of sulfonate anions in the presence of palladium catalysts [28][29]. They have also been used in the synthesis of the neuraminidase inhibitor (−)-oseltamivir [30] and the

• organocatalytic synthesis of 2-cyclohexen-1-ones via a Michael/Michael/retro-Michael cascade reaction [31]. Our research has shown that the Jørgensen–Hayashi catalyst [32][33] is a highly promising organocatalyst, facilitating enantioselective Michael addition reactions with high yields and excellent levels of

Photomechanochemistry: harnessing mechanical forces to enhance photochemical reactions

• Francesco Mele,
• Ana M. Constantin,
• Andrea Porcheddu,
• Raimondo Maggi,
• Giovanni Maestri,
• Nicola Della Ca’ and
• Luca Capaldo

Beilstein J. Org. Chem. 2025, 21, 458–472, doi:10.3762/bjoc.21.33

• transfer [13][14][15]. Regardless of the mechanistic details of the activation manifold, all photochemical reactions obey two laws: the Grotthuss–Draper and the Einstein–Stark laws [16]. The Grotthuss–Draper law dictates that only absorbed light can induce photochemical transformations within a system. In

• turn demands large volumes of solvents, negatively impacting the sustainability of light-mediated synthesis as it transitions from academic curiosity to industrial application. Moreover, since the solvent is the reaction component with the highest concentration, competitive side-reactions such as

• hydrogen-atom transfer or solvolysis are often observed. A technological solution to cope with the Beer–Lambert law was offered by flow chemistry [19][20][21] by employing microreactors with reduced optical paths to enhance irradiation efficiency [22][23][24]. Photon-limited reactions, whose efficiency is

Electrochemical synthesis of cyclic biaryl λ³-bromanes from 2,2’-dibromobiphenyls

• Andrejs Savkins and
• Igors Sokolovs

Beilstein J. Org. Chem. 2025, 21, 451–457, doi:10.3762/bjoc.21.32

• diaryl λ3-bromanes under remarkably mild conditions with subsequent applications of the in situ-generated arynes in cycloaddition reactions [3], meta-selective reactions with oxygen and nitrogen nucleophiles [4][5], regiodivergent meta or ortho-alkynylations [6], and regioselective (di)halogenation [7

• ]. In addition, cyclic diaryl λ3-bromanes have been successfully employed as halogen-bonding organocatalysts in Michael addition [8] and their chiral variants were efficient in catalyzing enantioselective Mannich reactions of ketimines with cyanomethyl coumarins [9] and malonic esters [10]. These

• improving the substrate scope and understanding the reaction mechanism are in progress in our laboratory. Synthesis of cyclic diarylbromonium compounds. Substrate scope. Reactions were performed on a 0.15 mmol scale. Yields were determined by 1H NMR spectroscopy of the reaction mixture using 1,2,3,4

New tandem Ugi/intramolecular Diels–Alder reaction based on vinylfuran and 1,3-butadienylfuran derivatives

• Yuriy I. Horak,
• Roman Z. Lytvyn,
• Andrii R. Vakhula,
• Yuriy V. Homza,
• Nazariy T. Pokhodylo and
• Mykola D. Obushak

Beilstein J. Org. Chem. 2025, 21, 444–450, doi:10.3762/bjoc.21.31

• yields. The studied tandem Ugi and intramolecular Diels–Alder reactions allow high substituent variation in the named isoindoles. Keywords: 1,3-butadienylfuran; furo[2,3-f]isoindole; intramolecular Diels–Alder reaction; isoindole; one-pot; Ugi reaction; vinylfuran; Introduction Energy-saving and

• environmentally friendly synthetic strategies, especially one-pot multicomponent and tandem reactions, are key to modern organic and medicinal chemistry [1][2][3][4][5][6][7] and have proven to be successful in generating diverse heterocyclic scaffolds, as highlighted in a recent book [8]. Multicomponent

• reactions, for instance, have contributed to high-throughput screening for drug discovery, facilitating the identification of new therapeutic compounds. [9][10]. A notable example is ivosidenib, approved in 2018, which was synthesized using the Ugi reaction to target mutated IDH1 in acute myeloid leukemia

Beyond symmetric self-assembly and effective molarity: unlocking functional enzyme mimics with robust organic cages

• Keith G. Andrews

Beilstein J. Org. Chem. 2025, 21, 421–443, doi:10.3762/bjoc.21.30

• Keith G. Andrews Department of Chemistry, Durham University, Lower Mount Joy, South Rd, Durham, DH1 3LE, UK 10.3762/bjoc.21.30 Abstract The bespoke environments in enzyme active sites can selectively accelerate chemical reactions by as much as 1019. Macromolecular and supramolecular chemists have

• across many fields of selective catalysis under the term confinement [3], a term borrowed from heterogeneous catalysis. Polarization can be understood as the catalyst providing an electrostatic environment that works to stabilize electron redistribution. Since all reactions redistribute electrons, and

• zeolites [28][29][30][31][32]. Undoubtedly property changes can occur in cavities, but those properties not covered by organization must be explicable: I would argue (for typical ground-state reactions) they are covered by the concept of polarization. Modern descriptions of enzyme active sites speak of

Identification and removal of a cryptic impurity in pomalidomide-PEG based PROTAC

• Bingnan Wang,
• Yong Lu and
• Chuo Chen

Beilstein J. Org. Chem. 2025, 21, 407–411, doi:10.3762/bjoc.21.28

• of 5 using the same sequence of reactions starting from 3-fluorophthalic anhydride instead of 1. Indeed, 5 is a white solid without UV absorption around 410 nm (Figure 2). The formation of 6 originated from nucleophilic acyl substitution to displace the glutarimide in 1 by 2. Interestingly, this side

• . Although C2’ and C4’ remain the most electropositive sites, we could not isolate any byproducts corresponding to reactions with glutarimide. The preferred nucleophilic reaction at C1, C3, and C4 can be explained by the fact that the LUMO of 1 resides entirely on phthalimide. The low SNAr reaction rate may

• sulfonate to the byproduct by reacting it with taurine allows for easy decontamination. This method may facilitate the purification of other similar reactions and improve the quality of related pomalidomide derivatives. The structures of veliparib and iVeliparib-AP6. Identification of the cryptic impurity

The effect of neighbouring group participation and possible long range remote group participation in O-glycosylation

• Rituparna Das and
• Balaram Mukhopadhyay

Beilstein J. Org. Chem. 2025, 21, 369–406, doi:10.3762/bjoc.21.27

• exhibits comparatively less efficacy in achieving complete stereoselectivity in the glycosylation reactions. Remote participation is a still highly debated topic in the scientific community. However, implementing the participating role of the remote groups in glycosylation reactions is widely practised to

• carbohydrate moieties [20][21][22] coupled with the need for suitable anomeric stereoselectivity [23]. Over the decades, there have been widespread studies to standardise and optimise glycosylation reactions, but a standard reaction protocol still eludes the scientific community. We will give a generalised

• temperature or the activation entropy, hydrogen bonding, solvent [24], nature of the leaving groups and the promoter used [25]. The mechanism of glycosylation reactions has long been categorised mostly as dissociative SN1 reactions proceeding through stabilised oxocarbenium ions with the role of counterions

Synthesis, structure, ionochromic and cytotoxic properties of new 2-(indolin-2-yl)-1,3-tropolones

• Yurii A. Sayapin,
• Eugeny A. Gusakov,
• Inna O. Tupaeva,
• Alexander D. Dubonosov,
• Igor V. Dorogan,
• Valery V. Tkachev,
• Anna S. Goncharova,
• Gennady V. Shilov,
• Natalia S. Kuznetsova,
• Svetlana Y. Filippova,
• Tatyana A. Krasnikova,
• Yanis A. Boumber,
• Alexey Y. Maksimov,
• Sergey M. Aldoshin and
• Vladimir I. Minkin

Beilstein J. Org. Chem. 2025, 21, 358–368, doi:10.3762/bjoc.21.26

• is to obtain heterocyclic indole compounds conjugated with a 1,3-tropolone moiety. The variability of the products of acid-catalyzed reactions in the series of 2,3,3-trimethylindolenine with 1,2-benzoquinone derivatives depends on the nature of the substituents in the 1,2-benzoquinone. Thus, the

• contraction and the formation of 2-azabicyclic products and pyridino[1,2-a]benzo[e]indol-10,11-diones [24]. o-Chloranil was found to be the most efficient 1,2-benzoquinone, which engages in o-quinone ring-expansion reactions with 2,3,3-trimethylindolenines to form hard-to-reach polychlorinated derivatives of

• reactions of 2-methylquinolines with 3,5-di-(tert-butyl)-1,2-benzoquinone [1] and benzophenones with o-chloranil [15]. The norcaradiene derivatives 5, formed in the next step by the intramolecular cyclization reaction of 4, undergo thermal isomerization into 2,3-dihydrotropolones 6. The formation of 2

Synthesis of new condensed naphthoquinone, pyran and pyrimidine furancarboxylates

• Kirill A. Gomonov,
• Vasilii V. Pelipko,
• Igor A. Litvinov,
• Ilya A. Pilipenko,
• Anna M. Stepanova,
• Nikolai A. Lapatin,
• Ruslan I. Baichurin and
• Sergei V. Makarenko

Beilstein J. Org. Chem. 2025, 21, 340–347, doi:10.3762/bjoc.21.24

• -d]pyrano[4,3-b]pyran-, furo[2',3':4,5]pyrano[3,2-c]chromene-, and furo[2,3-d]pyrimidine carboxylates were obtained from the reactions of alkyl 3-bromo-3-nitroacrylates with representatives of carbo- and heterocyclic CH-acids under simple conditions, without the use of organocatalysts. The structures

• furopyran, furocoumarin [9][10], and furopyrimidine series [11][12]. It is known that the main approaches to the synthesis of naphtho[2,3-b]furan-4,9-diones are reactions of hydroxynaphthalene-1,4-dione with ethane-1,2-diol [13], chloroacetaldehyde [14], ethenyl methyl sulfone [15], or ethenyl acetate [16

• reactions of 4-hydroxy-7-methyl-2H,5H-pyrano[4,3-b]pyran-2,5-dione and 4-hydroxy-2H,5H-pyrano[3,2-c]chromene-2,5-dione with ethynylbenzene [26] (Scheme 3). The possibility of the formation of substituted furan structures is shown by the example of the reaction of nitroalkenes with aliphatic CH acids [27

Red light excitation: illuminating photocatalysis in a new spectrum

• Lucas Fortier,
• Corentin Lefebvre and
• Norbert Hoffmann

Beilstein J. Org. Chem. 2025, 21, 296–326, doi:10.3762/bjoc.21.22

• become a powerful approach for achieving sustainable chemical transformations, combining high efficiency with energy-saving, mild conditions. By harnessing the deeper penetration and selectivity of red and near-infrared light, this method minimizes the side reactions typical of higher-energy sources

• , making it particularly suited for large-scale applications. Recent advances highlight the unique advantages of both metal-based and metal-free catalysts under red-light irradiation, broadening the range of possible reactions, from selective oxidations to complex polymerizations. In biological contexts

• driving chemical transformations under mild and efficient conditions. The use of red and near-infrared light enables deeper penetration into reaction media, reducing the high-energy side reactions commonly triggered by UV or blue light. These features make red-light photocatalysis particularly

Molecular diversity of the reactions of MBH carbonates of isatins and various nucleophiles

• Zi-Ying Xiao,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2025, 21, 286–295, doi:10.3762/bjoc.21.21

• Zi-Ying Xiao Jing Sun Chao-Guo Yan College of Chemistry & Chemical Engineering, Yangzhou University, Yangzhou 225002, China 10.3762/bjoc.21.21 Abstract In this paper, the nucleophilic substitution reactions of various N- and P-containing nucleophiles to MBH carbonates of isatins were investigated

• an indole motif with a ketone and a γ-lactam moiety occur in numerous natural substances [1][2][3][4]. Isatins have many interesting aspects in organic reactions and potential applications. The versatile reactivity of isatins used both as an electrophiles and nucleophiles and their easy availability

• reactions of isatins with alkyl acrylates, acrylonitrile, and other activated alkenes [26][27][28][29]. Due to the stronger electron-withdrawing effect of the oxindole motif, MBH carbonates of isatins showed higher reactivity than that of the normal MBH carbonates of normal ketones [30][31][32][33][34][35

Oxidation of [3]naphthylenes to cations and dications converts local paratropicity into global diatropicity

• Abel Cárdenas,
• Zexin Jin,
• Yong Ni,
• Jishan Wu,
• Yan Xia,
• Francisco Javier Ramírez and
• Juan Casado

Beilstein J. Org. Chem. 2025, 21, 277–285, doi:10.3762/bjoc.21.20

• attracted a growing interest in recent times, both from fundamental and technological reasons [9][10][11]. Antiaromaticity destabilizes the ground state of organic molecules by raising their highest energy occupied molecular orbitals, thus allowing for easy oxidation, doping, and electron-transfer reactions

Three-component reactions of conjugated dienes, CH acids and formaldehyde under diffusion mixing conditions

• Dmitry E. Shybanov,
• Maxim E. Kukushkin,
• Eugene V. Babaev,
• Nikolai V. Zyk and
• Elena K. Beloglazkina

Beilstein J. Org. Chem. 2025, 21, 262–269, doi:10.3762/bjoc.21.18

• main reaction products. Keywords: aldol condensation; [4 + 2]-cycloaddition; diffusion mixing; formaldehyde; Knoevenagel condensation; three-component reactions; Introduction Formaldehyde is a reactive electrophilic reagent widely used as a C1 building block in multicomponent reactions [1][2][3]. Its

• reactions that proceed through the formation of formaldehyde condensation products (Scheme 1). Previously, we have proposed a convenient diffusion mixing technique for multicomponent reactions based on the absorption of volatile reagent vapors by a mixture containing the remaining reaction components. This

• method was successfully used to generate highly active nitrile oxides and nitrilimines for 1,3-dipolar cycloaddition reactions [19][20][21]. Based on our previous experience with diffusion mixing, we assumed that formaldehyde vapor diffusion into the reaction would lead to an extremely low concentration

Synthesis of disulfides and 3-sulfenylchromones from sodium sulfinates catalyzed by TBAI

• Zhenlei Zhang,
• Ying Wang,
• Xingxing Pan,
• Manqi Zhang,
• Wei Zhao,
• Meng Li and
• Hao Zhang

Beilstein J. Org. Chem. 2025, 21, 253–261, doi:10.3762/bjoc.21.17

• ) gave more than moderate yields of the corresponding products. To evaluate the feasibility of the process in scale-up studies, gram-scale 2a was synthesized under optimized conditions. The reactions of 1a (1.760 g, 10 mmol) with H2SO4 (10 mmol) and TBAI (2 mmol) gave the corresponding 1,2-di-p

Effect of substitution position of aryl groups on the thermal back reactivity of aza-diarylethene photoswitches and prediction by density functional theory

• Misato Suganuma,
• Daichi Kitagawa,
• Shota Hamatani and
• Seiya Kobatake

Beilstein J. Org. Chem. 2025, 21, 242–252, doi:10.3762/bjoc.21.16

• family of photochromic compounds. This study explores the photochromic properties and thermal back reactivities of various aza-diarylethene regioisomers (N1–N4 and I1–I4) in n-hexane. These molecules exhibit fast thermally reversible photochromic reactions driven by 6π aza-electrocyclization. Kinetic

• absorption band in the visible region disappeared and returned to the initial one by stopping UV light irradiation. These results indicate that all molecules exhibit T-type photochromic reactions based on 6π aza-electrocyclic reaction. The absorption bands of compounds I1(c)–I4(c) are blue-shifted compared

• and the rate constants (k) of the thermal back reactions at various temperatures were determined (Figure 2b,e and Supporting Information File 1, Figure S3 and Tables S1–S6). Figure 2c and 2f, and Figure S4 in Supporting Information File 1 show the temperature dependence of k (Eyring plots) for

Visible-light-promoted radical cyclisation of unactivated alkenes in benzimidazoles: synthesis of difluoromethyl- and aryldifluoromethyl-substituted polycyclic imidazoles

• Yujun Pang,
• Jinglan Yan,
• Nawaf Al-Maharik,
• Qian Zhang,
• Zeguo Fang and
• Dong Li

Beilstein J. Org. Chem. 2025, 21, 234–241, doi:10.3762/bjoc.21.15

• of our ongoing interest in radical cyclization reactions [22][23][24][25][26], we report here a sustainable and efficient protocol for synthesizing difluoromethylated and aryldifluoromethylated polycyclic imidazoles via visible-light-promoted cyclization of unactivated alkene-containing imidazoles

• difluoroacetate anion. Conclusion In summary, we have successfully developed a sustainable and efficient method for synthesizing difluoromethylated and aryldifluoromethylated polycyclic imidazoles through visible-light-promoted radical reactions. In contrast to previous reports, we achieved high yields of